Observations of V694 Mon (MWC 560) requested for Chandra cam

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Observations of V694 Mon (MWC 560) requested for Chandra cam

文章 PTS » 週六 27 2月, 2016 13:16

AAVSO Alert Notice 538
February 26, 2016

Observations of V694 Mon (MWC 560) requested for Chandra campaign

Dr. Jeno Sokoloski (Columbia University) and Mr. Adrian Lucy
(graduate student, Columbia University) have requested AAVSO
observations of the jet-driving symbiotic star V694 Mon (MWC 560),
which is in outburst, in support of upcoming Chandra observations
to investigate the state of the inner accretion disk during this

The Chandra observations are scheduled (preliminary schedule)
for 2016 March 8 (7:17-14:13 UTC) and March 9 (2:20-9:17 UTC).

Beginning now and continuing through April 2016, Dr. Sokoloski
writes, "multi-band photometry (UBVRI, but especially UBV),
spectroscopy, and minute-time-resolution light curves of the
optical flickering are requested. Series of exposures in B or V
will be very interesting.

"[A paper by Tomov et al. in Nature (1990, 346, 637)] describes
optical spectroscopic evidence for jet acceleration during an
outburst in early 1990. Perhaps this eruption will show the same
sort of behavior. The current outburst is the first comparably
bright outburst of MWC 560 since that 1990 event. In the related
system CH Cyg, we saw changes in the amplitude and character of
the flickering when a jet was produced (Sokoloski & Kenyon 2003,
Ap.J., 584, 1021; e-print at http://arxiv.org/abs/astro-ph/0211040),
suggesting that the inner disk was disrupted and then rebuilt. We
are hoping to use any changes in the flickering from MWC 560 during
this outburst in a similar way to probe the structure of the inner

Mr. Lucy adds that "...it is possible we could see the re-formation
of the inner accretion disk following jet ejection over the next
couple months, which could be traced by watching the degree of
flickering change over time."

V694 Mon ranges between 8.8 and 12.7 V. Observations in the AAVSO
International Database show it at 9.224 V (+/-0.001) on 2016
February 25.2627 UT (SGEA, G. Stone, Auberry, CA), down from its
maximum brightness of about 8.8 V on 2016 February 10 (several

Coordinates: R.A. 07 25 51.28 Dec. -07 44 08.2 (2000.0)

AAVSO finder charts for V694 Mon with comparison stars may be
generated using the AAVSO Variable Star Plotter (VSP;

Please submit your observations to the AAVSO International
Database using the name 'V694 MON'.

This campaign is being followed on the AAVSO Observing Campaigns
page at https://www.aavso.org/observing-campaigns.

This AAVSO Alert Notice was prepared by Elizabeth O. Waagen.


Information on submitting observations to the AAVSO may be found at:


An Alert Notice archive is available at the following URL:

Subscribing and Unsubscribing may be done at the following URL:
https://www.aavso.org/observation-notif ... ertnotices


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